Process for the production of paste-forming polymers of vinyl chloride

Abstract

Paste-forming polymers of vinyl chloride are produced by discontinuous emulsion polymerization, adding to the polymerization charge, in a batchwise or continuous fashion, an emulsifier system comprising (a) alkyl sulfonates, alkylaryl sulfonates, or sulfosuccinates in amounts of 0.2-3% by weight, based on the amount of monomer, and (b) 50-200% by weight, based on the amount of surface active agent employed, of a C 14 -C 20 -alkyl alcohol. the PVC powders obtained yield pastes exhibiting low viscosities in both the low and high shear ranges.

What is claimed is: 
     
       1. In a process for producing a paste-forming polymer of vinyl chloride and 0-30 wt. % of a copolymerizable monomer comprising discontinuously polymerizing the monomers in the presence of a water-soluble catalyst and an emulsifier system, the improvement comprising, adding to the polymerization charge during the polymerization period, batchwise or continuously, an emulsifier system comprising:   (a) 0.2-3% by weight based on the total weight of the monomers, of an alkali metal or ammonium salt of an alkyl sulfonic acid of 10-20 carbon atoms in the alkyl group, of an alkylbenzene sulfonic acid of 8-18 carbon atoms in the alkyl group, or of a sulfonated succinic acid diesterified by a C 6-14  -alkanol; and   (b) 50-200% by weight, based on the amount of component (a) of a C 14  -C 20  -alkanol,   whereby at a conversion of 50%, at most half of the emulsifier system is added.   
     
     
       2. A process of claim 1 wherein emulsifier component (a) is an alkali metal or ammonium salt of a C 14-17  -alkylsulfonic acid. 
     
     
       3. A process of claim 1 wherein emulsifier component (a) is sodium decyl sulfonate, sodium dodecyl sulfonate, sodium myristyl sulfonate, sodium palmityl sulfonate, sodium stearyl sulfonate, sodium heptadecyl sulfonate, or sodium arachyl sulfonate. 
     
     
       4. A process of claim 1 wherein emulsifier component (a) is an alkali metal or ammonium salt of a (C 10-13  -alkyl)benzenesulfonic acid. 
     
     
       5. A process of claim 1 wherein emulsifier component (a) is sodium tetrapropylene benzenesulfonate, sodium p-n-dodecyl benzenesulfonate, sodium octadecyl benzenesulfonate, sodium octyl benzenesulfonate, sodium decyl benzenesulfonate, sodium tridecyl benzenesulfonate, sodium tetradecyl benzenesulfonate, sodium pentadecyl benzenesulfonate, or sodium hexadecyl benzenesulfonate. 
     
     
       6. A process of claim 1 wherein emulsifier component (a) is an alkali metal or ammonium salt of the sulfonate group of a sulfonated succinic acid alkyl ester wherein each alkyl ester group is of 8-10 C-atoms. 
     
     
       7. A process of claim 1 wherein emulsifier component (a) is sodium dihexyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium di-2-ethyl-hexyl sulfosuccinate, sodium didecyl sulfosuccinate, sodium didodecyl sulfosuccinate, sodium diisodecyl sulfosuccinate, sodium diisododecyl sulfosuccinate, sodium ditridecyl sulfosuccinate, or sodium ditetradecyl sulfosuccinate. 
     
     
       8. A process of claim 1 wherein emulsifier component (a) is a mixture of said sulfonates. 
     
     
       9. A process of claim 1 wherein emulsifier component (b) is myristyl alcohol, palmityl alcohol, stearyl alcohol, arachyl alcohol, 2-hexadecanol, or 2-octyldodecanol. 
     
     
       10. A process of claim 1 wherein the amount of emulsifier component (a) is 0.5-1.5% by weight and the amount of emulsifier component (b) is 70-150% by weight, both on the same basis as in claim 1. 
     
     
       11. A process of claim 1, wherein emulsifier component (a) is a sodium salt. 
     
     
       12. A process of claim 1, wherein the surface tension of the polymer dispersion during polymerization is maintained at a value that is 15 to 30% higher than the value of the surface tension belonging to a 2 weight % aqueous solution of the emulsifier used. 
     
     
       13. A process of claim 1, wherein 1-20 wt. % of a comonomer is employed and is vinyl acetate, vinylidene chloride, vinyl ether, acrylonitrile, or an acrylic acid ester. 
     
     
       14. A process of claim 1, wherein the weight ratio of monomers to water is 1:0.6 to 1:1.6. 
     
     
       15. A process of claim 1, wherein the polymerization temperature is 40°-70° C. 
     
     
       16. A process for producing a paste-forming polymer of vinyl chloride and 0 to 30% by weight of a copolymerizable monomer, the resultant polymer having low viscosity at low shear rates, comprising discontinuously polymerizing the monomer in the presence of a water soluble catalyst and an emulsifier system, and adding to the polymerization charge during the polymerization period, batchwise or continuously, an emulsifier system comprising: (a) 0.2-3% by weight, based on the total weight of the monomers, of an alkali metal or ammonium salt of an alkyl sulfonic acid of 10-20 carbon atoms in the alkyl group, of an alkylbenzene sulfonic acid of 8-18 carbon atoms in the alkyl group, or of a sulfonated succinic acid diesterified by a C 6-14  -alkanol; and   (b) 50-200% by weight, based on the amount of component (a) of a C 14  -C 20  -alkanol,   whereby at a conversion of 50%, at most half of the emulsifier system is added.   
     
     
       17. A process of claim 1 wherein component (a) is of the formula ##STR2## wherein R and R 1  are each C 6-14  -alkyl; and M is ammonium or an alkali metal.